This invention relates to a mobile communication system including a base station controller, a plurality of radio base stations connected to the base station controller, and a mobile station simultaneously communicable with the radio base stations and, in particular, to packet retransmission control from the mobile station to the radio base stations when a packet is transferred from the base station controller through the radio base stations to the mobile station.
For example, a conventional mobile communication system is disclosed in Japanese Unexamined Patent Publication (JP-A) No. H 11-341541. As illustrated in FIG. 1, the mobile communication system disclosed in the publication comprises a base station controller 120 connected to a communication network 110, a plurality of base stations 130-1 and 130-2 connected to the base station controller 120, and a mobile station 140. The mobile station 140 transmits and receives packetized data through radio channels to and from the base stations 130-1 and 130-2 each of which is communicable with the mobile station 140.
In the above-mentioned mobile communication system, a packet transferring method disclosed in the above-mentioned publication is used in case where the mobile station 140 transmits a transmission packet to the base station controller 120 through each of the two base stations 130-1 and 130-2. In this case, the base station controller 120 receives two transmission packets transferred through the two base stations 130-1 and 130-2, respectively, and selects, as a selected packet, one of the two transmission packets which has a smaller number of transmission errors. The base station controller 120 transfers the selected packet to the communication network 110.
However, the above-mentioned publication does not disclose packet retransmission for the purpose of reducing the transmission errors.
In particular, the above-mentioned publication does not disclose packet retransmission control from the mobile station to the radio base stations when a packet is transferred from the base station controller through the radio base stations to the mobile station.